Hydrodynamically driven piezocatalytic activation of peracetic acid by MoS2 for atrazine degradation

Hydraulic disturbance during sand-filter backwashing can release retained micropollutants, yet the same disturbance represents an underused source of mechanical energy. Here, a hydraulic driven MoS 2 /peracetic acid (PAA) piezocatalytic system was developed for the degradation of atrazine (ATZ). The MoS 2 /PAA system exhibited substantially higher reactivity than the PAA, MoS 2 /H 2 O 2 , and MoS 2 /PMS systems, indicating a strong synergistic interaction under hydraulic conditions. Increasing the hydraulic gradient further enhanced ATZ degradation. Mechanistic investigations revealed that hydraulic stimulation induced piezoelectric polarization of MoS 2 , facilitating charge separation and activating PAA via a direct electron-transfer pathway. As a result, multiple reactive species were generated, including •OH, R-O•, and 1 O 2 , with 1 O 2 playing a dominant role. Transformation pathway analysis indicated that ATZ degradation proceeded mainly through alkyl hydroxylation, dechlorination, and dealkylation. Although background water constituents inhibited degradation to varying extents, the system maintained good stability with low Mo leaching. Toxicity prediction further suggested an overall decrease in ecotoxicity during degradation. Unlike conventional piezocatalytic processes driven by ultrasound or dedicated mechanical devices, this system directly utilizes the hydraulic disturbance generated during sand-filter backwashing. These findings demonstrate a self-powered strategy for efficient and environmentally relevant removal of persistent organic pollutants.